import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.Socket;
import java.net.SocketException;

/**
 * @Author liangzai
 * @Description:
 */
public class UdpEchoServer {
    private DatagramSocket socket = null;
    private int port;

    public UdpEchoServer(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    private void start() throws IOException {
        System.out.println("服务器启动!");
        while(true){
            DatagramPacket requestPacket = new DatagramPacket(new byte[4090],4090);
            //接收请求 数据报
            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(),0,requestPacket.getLength());
            //对请求处理，发出响应
            String response = process(request);

            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(),response.getBytes().length,
                    requestPacket.getSocketAddress());
            socket.send(responsePacket);

            System.out.printf("[%s,%d] repuest : %s response : %s\n",requestPacket.getAddress(),requestPacket.getPort(),
                    request,response);

        }
    }

    private String process(String requestPacket){
        return requestPacket;
    }

    public static void main(String[] args) throws IOException {
        UdpEchoServer server = new UdpEchoServer(9090);
        server.start();
    }
}
